Investing in interviewing.io: Modernizing Recruiting for Engineers
M13 is proud to lead interviewing.io’s $10 million Series A to help more engineers get hired faster.

interviewing.io
Ten years ago, we realized that software is eating the world. Early internet trailblazers like Facebook, Amazon, Google, and Twitter were growing at an accelerating pace, leaving industry incumbents who were too slow to adapt to the digital world in their wake.
At that time, there were fewer than 1 million software engineers in the U.S. tasked with building the programs eating the world. Fast forward to today, and that number has more than quadrupled to 4.4 million. And what do the next 10 years look like? The software engineer job market is expected to grow 22% over the next decade—that’s five times the growth rate of the average U.S. job market.
And with that tremendous job sector growth, recruiters in the U.S. are unfortunately scrambling to find the most talented candidates for the 1 million unfilled software engineer positions—all while using outdated (and often biased) sourcing models and interviewing practices. We believe there is a better way to both identify the best candidates and increase access to engineering roles.
That’s why we’re proud to lead the $10 million Series A for interviewing.io, a platform for job-seeking engineers to improve their technical interviewing skills and get hired faster.
The shortage of engineering talent isn’t from a lack of effort. A typical engineering search can take more than 220 cumulative hours over a three-month process that includes:
1
Sourcing new candidates
2
Recruiter phone screens
3
Engineer phone interviews
4
Candidate onsites
5
Interviewing committee deliberations

Founded in 2015 by Aline Lerner, interviewing.io is a marketplace for engineering candidates to practice anonymous technical interviews and get hired faster at top companies. For recruiters, the platform can identify candidates who are already considering new jobs (because they’re actively practicing technical interviews)—in fact, interviewing.io can reduce recruiting time by as much as 80%. The platform also eliminates resumes and subjective measurements to focus instead on the most relevant skills and qualifications for software engineers.
As an engineer herself, Aline is one of the strongest examples of founder-market fit in the M13 portfolio. After all, the MIT grad worked as a software engineer before shifting to running technical recruiting at multiple tech companies and then starting her own boutique technical recruiting firm. Aline’s firsthand experience gives her deep empathy for engineering candidates, and she has instilled the core value of “putting candidate experience first” in the platform.

Here’s how the three-sided marketplace works:
1. Engineering candidates (supply)
Engineers looking to improve their technical interviewing skills sign up for 60-minute slots. Each virtual interview is designed to simulate the real thing with an experienced engineer on the other side asking the questions.
Mock interviews are all anonymized—if you’re practicing for your upcoming Google interviews with an interviewer from Google, for example, a bad interview won’t hurt your chances with the company. After the mock interview, the interviewer provides real-time feedback so the candidate can understand where and how to improve.
2. Experienced engineers (supply)
The interviewers on the platform include senior engineers from FAANG—Facebook, Amazon, Apple, Netflix, Google—and other tech companies who sign up for multiple 60-minute interviews each week and receive a cut of each interview fee. With this evergreen marketplace model, demand is clearly feeding supply—of all the interviewers on the platform, more than half were previously candidates on interviewing.io.
3. Companies (demand)
Having hosted about 100,000 technical interviews since 2015, interviewing.io aggregates interview scores based on technical skills, problem solving, and communication skills. The top 3% of interviewees receive access to a job portal where recruiters can select top-performing candidates for first-round technical screens. Customers include Facebook, Amazon, Lyft, Uber, Snap, and Dropbox. These initial interviews are also anonymous, and the employer only learns the identities of candidates who pass the company’s screen.

Research has demonstrated that the current hiring system can often be biased against underrepresented groups. It’s not surprising given the amount of candidates a typical tech recruiter needs to meet and hire that they would opt for easy heuristics. But interviewing.io gives a better, more predictive way to assess talent that removes bias, and that means more access to historically marginalized candidates.
By maintaining a candidate’s anonymity throughout, the platform helps shift recruiters from subjective resume-based sourcing toward an objective skill-based criteria. In doing so, the measure of assessment properly switches to coding skill, rather than where the candidate went to school or who is in their network. This provides a more diverse pool of candidates for each company—engineers from nontraditional backgrounds represent 40% of hires made through the platform, many of whom had previously been rejected by the same company that eventually gave them the offer.
In addition, the platform also offers greater access to all candidates through its payment deferral program—job-seekers can practice up to five interviews at no upfront cost, paying only after landing a job.
Given the company’s 5x year-over-year growth, it’s clear the marketplace is working for both engineers and recruiters alike.
- Candidates who do five or more mock interviews on the platform can double their likelihood of getting hired.
- Improved interview performance can account for up to a $50K boost in compensation offered.
- 94% of interviewing.io users land jobs within 4 months of beginning their practice on the platform.
- Recruiters on average fill a role 3.5x faster because they’re only seeing qualified and vetted candidates in their pipeline.
Congratulations to Aline and the rest of the interviewing.io team on your Series A—we’re proud to support you in your mission to make the entire technical recruiting process more powerful and accessible for engineers and recruiters.